Shearing and classifying mechanism for metal strip



Nov. 28, 1944. A. M. DEXTER, JR 2,363,577

SHEARING AND CLASSIFYING MECHANISM FOR METAL STRIP Filed Feb. 26 1942 2Sheets-Sheet l Nov. 28, 1944.

A. M. DEXTER, JR

2 Sheets-Sheet 2 Filed Feb. 26, 1942 NQN ATTORNEY Patented Nov. 28, 1944UNITED STATES PATENT OFFICE SHEARING AND CLASSIFYING MECHANISM FOR METALSTRIP Albert M. Dexter, Jr., Hartford, Conn., assignor toNlles-Bement-Pond Company, West Hartford, Conn., a corporation or NewJersey Application February 26, 1942, Serial No.-432,4 59

(c1. zoo-as) 8 Claims.

gate off-gage sheets from those that are within predetermined thicknesslimits.

In classifying sheets cut from strip material as it is being sheared andstacked it is important, if any part of what will become an individual apredetermined thickness, that the classifier gate be actuated toclassify the sheet, after being sheared, with other off-gage sheets andnot with sheets that are of correct thickness. Sheets may be extremelylong or short and the oil-gage portion of a sheet (gaged before it issheared) may be adjacent either the front or the trailing edge. Theclassifier gate therefore must be actuated whenever an off-gage portionis detected before the front edge of that particular sheet passes theclassifying gate. This actuation of the gate must take place at theproper time regardless of what particular portion of the sheet has beenindicated to be oil-gage and regardless of the length of the sheet.

It is an object, therefore, of the invention to gage a strip of materialcontinuously prior to its being sheared into individual sheets and toprovide a variable time delay means to actuate a classifier gate in timeto divert an oiI-gage sheet when it reaches the classifier gateregardless of the length of the sheet being sheared and regardless ofwhat portion of the sheet is indicated to be off-gage.

A featureof the invention that is important is that a circuit is closedmomentarily for each cutting movement of the shear blade or drum and ata particular position in the cycle of movement of the shearing member,this circuit energizing a solenoid to position a pin or othersettingmember if any oil-gage material has been detected within the length of asingle sheet, and the pin or other setting member, after a predeterminedbut adjustable period of time to permit the sheet to pass along aconveyor, serves to close a circuit to actuate the classifier gate todivert the off-gage sheet from the path of the normal sheets.

sheet is off-gage either by being above or below Another object of theinvention is to close an auxiliary control circuit as soon as a portionof a strip being sheared is indicated to be offgage, this controlcircuit remaining closed until the solenoid for operating the pinsetting device is energized by the rotation of the shear drum to closethe circuit of this solenoid. At that-instant the pin positioningsolenoid is operated to position the pin to close the classifier gatecircuit. Immediately after this'takes place. both the control circuitand solenoid operating circuit open and remain open until anotheroff-gage indication occurs. In any case, however, the classifier gatedoes not operate until the pin actuated by an off-gage indication of thestrip has moved in timed relation to the conveyor to a position to closethe gate operating circuit. This latter time delay may be varied inaccordance with the distance between the shear blade and the gate.

With the above and other objects in view, the invention may include thefeatures of construction and operation set forth in the followingspecification and illustrated in the accompanying drawings.

In the accompanying drawings annexed hereto and forming a part of thisspecification, I have shown the invention embodied in a shearing andclassifying mechanism for metal in strip form, but it will be understoodthat the invention can be otherwise embodied and that the drawings arenot to be construed'as defining or limiting the scope of the invention,the claims appended to this specification being relied upon for thatpurpose. I

In the drawings:

Figure 1 is a diagrammatic view in elevation of a shearing andclassifying mechanism in which the present invention is incorporated;and

Fig. 2 is a diagram of the'electrical circuits therefor.

In the above mentioned drawings I have shown but one embodiment of theinvention which is now deemed preferable, but it is'to be understoodthat changes and modifications may be made within the scope of theappended claims without blades; third, a conveyor belt for advancing theindividual sheets, after being sheared, to the classifier; fourth, aclassifier gate positioned at the end of the conveyor belt; fifth, acontactor closed momentarily once during each cutting movement of theshears; sixth, a mechanical timing device having movable members andoperated in timed relation to the speed of the conveyor belt; seventh,means to efifect movement of saidmembers when the gage indicates thatthe strip thickness is' above or below a predetermined dimension and theshear operated switch is closed; and eighth, a circuit closed when adisplaced movable member in the timing device passes aswitchpositionedat a predetermined distance from the displacing means, this lattercircuit energizing a sheared into sheets of any predetermined length andclassifiedv in accordance with variations in its thickness. Sheetshaving a thickness throughout their length within predetermined 'limitsfor which a gage I I is adjusted are stacked together after passing overa classifier gat I2; and sheets, any portion of which is above or belowthese predetermined limits, are diverted by the classifier gate I2actuated by the gage ,II

through circuits presently to be described so that :2

the oif-gage-sheets may be separately stacked.

Material unwound from the roll III passes first through cleaning stripsI3 andthen between the opposed rollers of gage II suchas an"electrolimit" gage. After passing the gage II the material passesthrough feeding and straightening rolls I4 and then is sheared by meansof revolving shear drums I5 within whichar placed cooperating shearingblades I6. After being sheared the separated sheets pass along aconveyor belt I1 to the classifier gate I2. In the position of the gateI2 shown in full lines, sheets within the gaging limits {or which themechanism is set are passed over the gate I2 to be stacked by means notshown. If any portion of. a sheet has been indicated by the gage II tobe off-gage, that is, above or below predetermined gage readings forwhich the gage II has been set, the gate I2 is raised to the P sitionindicated in dotted lines so that the off-gage or defective sheet ispassed below the gate I2 to be stacked separately from the qualifiedsheets. It will be understood that the movement of the strip .and therotation of the shearing drums I5 will be adjusted to cut the strip intosheets of the desired length.

i As stated above and as shown in the drawings, the gage I I throughwhich the strip passes before being sheared is an "electrolimit gage andvisually indicates variations in thickness by varying positions of thepointer of a milliammeter or other electric indicating instrument I8(see Fig. 2) over a dial or scale. This instrument I8 as shown in thediagram is coupled electrically to induction coils I9 between which isdisposed an armature 20 the position of which between the coils isvaried by variations in thickness of the strip being gaged and sheared.As this type of gage is fully described in the patent to Terry et al.No.- 2,115,351, granted April 26, 1938, further description is thoughtto be unnecessary.

Variable voltages within the coils I9 are induced by different positionsof the armature 2|) and the resultant voltage in the coils I9, afterbeing rectified, biases the pointer of the indicat= solenoid to actuatethe classifier gate. Referring more .in detail to the figures ofthedrawings, there is shown at III a roll of strip material such as thinsteel which is to be gaged,

ing instrument I8. Coils I9 are parts of a bridge circuit includingfixed coils 2I, the circuit being energized from a. transformer 22, theprimary winding of which is connected to a suitable A. C. source 23.

The resultant A. C. voltage across the terminals of coils I9 which isapplied across rectifier R is proportional to the unbalance of the gagebridge circuit which includes the coils I9 and is proportional-tovariations in thickness of the sheet steel as indicated by the gage Ii.This A. C. voltage from the terminals of coil I9 is amplified in vacuumtube VI vand is further am+ plified in the first triode unit of a duplextube V2. The output of this triode unit is fed into the second triodeunit of duplex tube V2 which is operated as a diode. tion of this diodea. D. C. voltage is developed across resistor network RNI. Tube V3,prefer: ably a gas-filled Thyratron, is connected to this network so asto leave a positive voltage on its grid, this voltage being taken fromthe tap on a grounded bleeder resistor T. The positive voltage isimpressed on this resistor by tube S acting as a rectifier. Thispositive voltage on the grid of tube V3 is opposed by the D. C. voltagedeveloped across resistor network RNI by the action of the diode unit ofV2. The net voltage on the grid of V3 is, therefore, the differencebetween these two voltages, and it is this difference that causesThyratron V3 to ignite and extinguish. When V3 is ignited by sufiicientvoltage difference, relay A, presently to be more fully described, isclosed as its coil is energized. The oircuit.V2-RNI--V3 constitutes afirst measuring circuit.

Vacuum tubes V2 and V3 are operated similarly to tubes V2 and V3. V2 andV3 being used when the strip is undersize or below a predeterminedthickness, and V2 and V3 when the strip is oversize. The only differencein the two circuits is in the resistor networks RNI and RNZ which areadjusted respectively to bias their Thyratrons V3 and V3 differently sothat they will ignite at difierent voltages from the gage bridge andenergize the relay coils A or B. The circuit V2 '-RN2V3 constitutes asecond measuring circuit. Vacuum tube VI is an amplifier common to bothcircuits.

Measuring relay A will be closed whenever its coil is energized byfiring of tube V3 which occurs when the gage I I indicates that thestrip is undersize or below gage, and measuring relay B is closedwhenever its coil is deenergized which occurs when the gage II indicatesthat the strip is oversize. Relay A is normally open, that is. is openwhen the strip being gaged is within predetermined limits, but isinstantly closed when V3 ignites simultaneously with the indication fromthe gage II that the strip is under gage and energizes its coil. Thecontacts of relay B are normally open, that is, they are open when thestrip is within predetermined limits, as tube V3 is normally firing andenergizing its coil. The contacts of relay B are closed when V3extinguishes simultaneously when the gage indicates over-gage anddeenergizes its coil. When the gage indicates undersize both tubes V3and V3 conduct and relay A is closed. When the gage indicates oversizeboth tubes V3 and V3 are extinguished and relay B is closed by gravity.When the gage indicates the strip to be within predetermined tolerances,V3 is extinguished and V3 is conducting so that both relays A and B areopen.

The contacts on relays A and B are paralleled By the rectification ac-Switch H also should open before the leading so as to energize the coilof a tolerance relay 0 when either A or Bis closed, that is when V3fires or V3 is extinguished in accordance with the strip going eitheroveror under-gage. Through the holding circuit comprising the holdingcontact on relay D and contact Cl of relay C, the coil of relay C locksitself in. Contact C2 is therefore held closed whenever relay A or 13 isclosed by the strip going oil-gage, and continues closed even though Aor B then opens.

iii

edge of what will be the next sheet after shearing enters the gagerolls.

To summarize the operation of these circuits: The strip may go off-gageand then immediately return on-gage again. When this happens relay Cwill lock-in, but the closing of its relay con- The circuit connected tocontacts C2 constitutes a preparatory circuit which is closed when relayC is energized. Through the action of rotary switch H actuated by theshear drum and momentarily closed once foreach sheet regardless oi G isalso energized through contact F3 to actuate a setting pin presently tobe referred to.

Contact Fl parallels contact E2 for the purpose of maintaining currentto the coil of relay F after drum switch H opens, thus deenergizingrelay E and consequently opening E2; this taking place only when thesteel strip is indicated by gage I l to be oil-gage (either above orbelow its limits), thus actuating either relay A or B closed. Thecircuit connected to contacts Fl constitutes interlocking means forkeeping relay F closed after relay E opens, as long as an off-gagecondition is indicated.

Contact F2, in series with contact E3, parallels C2 for the purpose ofmaintaining the current to the coil of relay F after relay A or B opens.Belay A or B would open if the steel strip returned to within its limitsat this time, which would otherwise deenergize relay F. Relay F is thusmaintained in an energized condition if the contacts of either relay Aor B are kept closed, even while relay E is alternately closed andopened by switch H.

Also relay F is kept energized even if A or B opens, until switch Hopens again for the first time after relays A or B open. When switch Hcloses for the first time after relays A ,or B open, the coil of relay Eis thereby energized,

thus closing switch El which energizes reset and holding relay D. Thisopens the normally closed contact of re-set and holding relay D, thusbreaking the interlock through holding contact Cl of the coil of relayC. Contact E3, however, because it closes at the same instant that Elcloses, is able to short across contacts C2 before relay D is able topick-up and break the interlock of relay C, thus the relay F is keptenergized through contacts E3 and its own contacts F2.

When the switch H opens, E is deenergized, and contact E3 opens, thusbreaking the current to the coil of relay F through contacts E2, E3, andF2. The entire system is thus restored to its original condition and.remains in that condition until there is another off-gage indication.

substantially at the instant the trailing edge of what will be anindividual sheet after shearing has passed the gage rolls and yet shouldallow the circuit to lock-in before the switch H opens again.

The rotary switch H is arranged so that it closes tacts will notimmediately effect the solenoid G as this effect must wait until rotaryswitch H closes. When H does close, solenoid G immediately will beenergized and will stay energized until H again opens. The period duringwhich the switch Hremains closed during the cycle of operation of theshear drum is extremely short and much Tess than the time taken by onesheet length, however short, to pass through the gage II. The circuit isthen restored "to its original condition instantaneously with theopening of switch H.

If the strip goes off-gage and stays off-gage, solenoid G will beenergized as soon as switch H closes. Should thestrip still be off-gagewhen H opens, the solenoid G will remain energized without interruption.The solenoid G will remain energized until H opens for the first timeafter the strip has returned to an on-gage condition. As soon as thestrip is again on-gage the circuit will be restored to normal. Duringall the time solenoid G is energized, setting pins 25 will continue tobe moved to a switch closing position, one pin or more being moved foreach in-.

dividual sheet.

If the strip should go off-gage at the very moment that H closes, theeffect of this closing will carry immediately through and solenoid Gwillbecome energized and stay energized until. H

again opens for the first time after the strip has returned to anon-gage condition. As soon as this switch H opens, the circuit willresume its normal condition and return the gate l2 to its lowerposition.

Any off-gage indication by the gage l l, whether it occurs adjacent theleading or trailing edge of what will become a single sheet when shearedfrom the strip, will energize the coil of relay C and set the circuitsto energize relay F and operate solenoid G as soon as relay coil E hasbeen energized by closing of the shear operated rotating switch H. Alsopromptly after the switch H opens the circuits will return to normal ifthe gage again indicates on-gage, so that the only sheets separated bythe classifier gate l2 will be those having ofif-gage indications.

The above description covers the mechanism and circuits employed foreffecting operation of the solenoid G wh ch effects movement of thesetting .pins or members 25 in a mechanical time delay mechanism. Thetime delay mechanism is shown diagrammatically in Fig. l and may besimilar to that shown and described in the patent to Ladrach 2,217,342granted October 8, 1940. In this form of delay mechanism a drum 26 isslowly rotated by connections 21 from the conveyor and in timed relationto the speed of travel of the conveyor. The particular means shown forrotating the drum include a chain drive from a pulley over which theconveyor passes which drives a worm meshing with a worm gear rotatablewith the drum. The movable members'or pins 25 are inserted about theperiphery of the drum and extend parallelly with the drum axis .in acircular series. These pins 25 are contacted by and moved to the rightas seen in this figure whenever solenoid G is energized. When the drum26 has rotated a distance corresponding to the distance from the leadingedge of a sheet to,

and by varying the angular distance between the 7, position where thepins 25 are actuated by sole e" noid G and the position where the pins25 close switch 28, the delay can be widely varied.

I claim as my invention:

1. In classifying apparatus for classifying sheet material, means forfeeding sheet material along a designated route, an inspection stationon said route and a shearing station on said route for shearing saidmaterial into desired lengths, a classifying station comprising aclassifying gate for selectively delivering sheared sheets into aperfect stack or an imperfect stack, said inspection station comprisinginspection means electrically responsive to the condition of saidmaterial as to a desired characteristic thereof, electrical meansconnected to said inspection means and comprising controlled contactsand being adapted to close its said contacts upon observation at saidinspection station of a departure from an established standard tolerancefor said characteristic, a holding circuit for said electrical means forretaining its contacts closed, cyclically actuated switch meanscontrolled by said feeding means and actuated to be closed at the momentof the passage past said inspection station of the trailing edge of eachof said lengths, electromagnetic gate actuating means for displacingsaid gate for selectively delivering sheets into a desired stack, apreparatory circuit controlled by the contacts of said electrical means,electromagnetic control means connected for actuation by said switchmeans, means actuated by said electromagnetic control means forcompleting said preparatory circuit and immediately thereafter openingsaid holding circuit so as to prepare said electrical means for theinspection of the succeeding length, and means controlled by thecompletion of said preparatory circuit for actuating said gate actuatingmeans.

2. In classifying apparatus for classifying sheet material, means forfeeding sheet material along a designated route, an inspection stationon said route and a shearing station on said route for shearing saidmaterial into desired lengths, a classifying station comprising aclassifying gate for selectively delivering sheared sheets into aperfect stack or an imperfect stack, said inspection station comprisinginspection means electrically responsive to the condition of saidmaterial as to a desired characteristic thereof, electrical meansconnected to said inspection means and comprising controlled contactsand being adapted to close its 'saidcontacts upon observation at saidinspection station of a departure from an established standard tolerancefor said characteristic, a holding circuit for said electrical means forretaining its contacts closed, cyclically actuated switch meanscontrolled by said feeding means and actuated to be closed at themomentof the passage past said inspection station of the trailing edgeof each of said lengths, electromagnetic gate actuating means fordisplacing I said gate for selectively delivering sheets into a desiredstack, a preparatory circuit controlled by the contacts of saidelectrical means, electromagnetic control means connected for actuationby said switch means,- means actuated by said electromagnetic controlmeans for completing said preparatory circuit and for maintaining thesame closed as longas said switch means is closed, said last mentionedactuated means also serving immediately after completing the preparatorycircuit for opening said holding circuit so as to prepare saidelectrical means for the inspection of the succeeding length, and meanscontrolled by the completion of said preparatory circuit for actuatingsaid gate actuating means.

3. In classifying apparatus for classifying sheet material, means forfeeding sheet material along a designated route, an inspection stationon said route and a shearing station on said route for shearing saidmaterial into desired lengths, a classifying station comprising aclassifying gate for selectively delivering sheared sheets into aperfect stack or an imperfect stack, said inspection station comprisinginspection means electrically responsive to the condition of saidmaterial as to a desired characteristic thereof, electrical ated switchmeans controlled by said feeding means and actuated to be closed at themoment of the passage past said inspection station of the trailing edgeof each of said lengths, electromagnetic gate actuating means fordisplacing closed as long as said controlled contacts of said electricalmeans are closed notwithstanding the opening of said switch means, saidlast mentioned actuated means also serving immediately after completingthe preparatory circuit for opening said holding circuit so as toprepare said electrical means for the inspection "of the succeedinglength, and means controlled by the completion of said preparatorycircuit for actuating said gate actuating means.

4. In classifying apparatus for classifying sheet material, means forfeeding sheet material along a designated route, an inspection stationon said route and a shearing station on said route for shearing saidmaterial into desired lengths, a-

classifying station comprising a classifying gate perfect stack or animperfect stack, said inspection station comprising inspection meanselectrically responsive to the condition of said material as to adesired characteristic thereof, electrical means connected to saidinspection means and comprising controlled contacts and being adapted toclose its said contacts upon observation at said inspection station of adeparture from an established standard tolerance for saidcharacteristic, a holding circuit for said electrical means forretaining its contacts closed, cyclically actuated switch meanscontrolled by said feeding means and actuated to be closed at the momentof the passage past said inspection station of the trailing edge of eachof said lengths, electromagnetic gate actuating means for displacingsaid gate for selectively delivering sheets into a desired stack. apreparatory circuit controlled by the contacts ofsaid electrical means,electromagnetic control means connected for actuation by said switchmeans, means actuated by said electromagnetic control means forcompleting said preparatory circuit and immediately thereafter openingsaid holding circuit so as to prepare said electrical means for theinspection of the succeding length, and means controlled by thecompletion of said preparatory circuit for actuating said gate actuatingmeans, said last mentioned actuated means further acting to shunt saidcontacts of said electrical means so as to prevent the opening of thecompleted preparatory circuit in the event that the length registers offstandard at the moment when said switching means is operated. I

5. In classifying apparatus for classifying sheet material, means forfeeding sheet material along a designated route, an inspection stationon said route and a shearing station on said route for shearing saidmaterial into desired lengths, a classifying station comprising aclassifying gate for selectively delivering sheared sheets into aperfect stack or an imperfect stack, said inspection station comprisinginspection means electrically passage past said inspection station ofthe trailing edge of each of said lengths, electromagnetic gateactuating means for displacing said gate for selectively deliveringsheets into a desired stack, a preparatorycircuit controlled by thecontacts of said electrical means, electromagnetic control meansconnectedfor actuation by said switch means and having a controlledcircuit comprising'serially connected therein said preparatory circuit,said controlled circuit being connected for actuating said gateactuatingmeans, interlocking means actuatable upon actuation of said controlmeans for keeping said controlled circuit in condition for maintainingsaid gate actuating means in operated condition as long as an offstandard observation is registered at said inspection stationnotwithstanding the return of said control means to unac'tuatedcondition.

6. In classifying apparatus for classifying sheet material, means forfeeding sheet material along a designated route, an inspection stationon'said route and a shearing station on said route for shearing saidmaterial into desired lengths, a classifying station comprising aclassifying gate for selectively delivering sheared sheets into aperfect stack or an imperfect stack, said inspection station comprisinginspection means electrically responsive to the condition of saidmaterial as to a desired characteristic thereof, electrical meansconnected to said inspection means and comprising controlled contactsand being adapted to close its said contacts upon observation at saidinspection station of a departure from an established standard tolerancefor said characteristic, a holding circut for said electrical means forretaining its contacts closed, cyclically actuated switch meanscontrolled by said feeding means and actuated to be closed at the momentof the passage past said inspection station of the trailing edge of eachof said lengths, electromagnetic gate actuating means for displacingsaid gate for selectively delivering sheets into a desired stack, apreparatory circuit controlled by the contacts of said electrical means,electromagnetic control means connected for actuation by said switchmeans and having a controlled circuit comprising'serially connectedtherein said preparatory circuit, said controlled circuit beingconnected for actuating said gate actuating means, interlocking meansactuatable upon actuation of said control means for keeping saidcontrolled circuit in condition for maintaining said gate actuatingmeans in operated condition as long as said switch means is closednotwithstanding the opening of the contacts of said electrical means,and means associated with said control means and, with said holdingcircuit of said electrical means operable upon actuation of said controlmeans for opening said holding circuit after the actuation of saidinterlocking means has bee completed. i 7. In classifying apparatus forclassifying sheet material, means for feeding sheet material along adesignated route, an inspection station on said route and a shearingstation on said route for shearing said material into desired lengths, aclassifying station comprising a classifying gate for selectivelydelivering sheared sheets into a perfect stack or an imperfect stack,said inspection station comprising inspection means electricallyresponsive to the condition of said material as to a desiredcharacteristic thereof, electrical means comprising a tolerance relayhaving normally open control contacts and being connected to saidinspection means and being adapted to energize and close said tolerancerelay upon observation at said inspection station of a departure from anestablished standard tolerance for said characteristic, a re-set relayhaving its contacts normally closed, holding contacts and a holdingcircuit for said tolerance relay and connected through the contacts ofsaid re-set relay, cyclically actuated switch means controlled by saidfeeding means and being arranged to be actuated to close at the momentof the passage past said inspection station of the trailing edge of eachof said lengths,

a course relay having its actuating winding connected to said switchmeans and having normally open control contacts, -eelctromagneticsetting means comprising a setting relay, means controlled by actuationof said setting means for displacing said gate for selectivelydelivering sheets into a desired stack, a control circuit connected tothe actuating winding of said setting means and being connected inseries through the control contacts of said tolerance relay and saidcourse relay, normally open auxiliary contacts for said course relayconnected to the actuating winding of said re-set relay, a first set ofholding contacts for said setting relay connected in parallel with thecontrol contacts of said course relay, a second set of holding contactsfor said setting relay, and an interlocking holding circuit connected tosaid second set of holding contacts and connected to the controlcontacts of said tolerance relay. and comprising connected in series anormally open interlocking set of contacts for said course relay, saidcourse relay and re-set relay being so constructed and arranged thatupon actua. tion of said course relay said interlocking set of contactsclose before said auxiliary contacts cause actuation of said re-setrelay to open the holding circuit of said tolerance relay.

8. Classifying apparatus as set forth in claim 1, said electrical meanscomprising a first measuring circuit and a first measuring relay therebyactuated and having open contacts when unactuated, said first measuringcircuit being arranged to respond to observation of a deficiency in saiddesired characteristic beyond the standard tolerance by actuating saidfirst measuring relay to close the contacts thereof, said electricalmeans further comprising a separate second measuring circuit and asecond measuring relay thereby actuated and having closed contacts whenunactuated, said second circuit being arranged to maintain said,

second measuring relay energized in response to observation of tolerablevalues of the desired characteristic and to deenergize said second relayin response to observation of excess of said desired

